Some of the piezoelectric elements have a structure in which a piezoelectric layer (piezoelectric film) made of a piezoelectric material capable of electromechanical conversion, such as a crystallized dielectric material, is disposed between two electrodes. This type of piezoelectric element is used as a deflection vibration mode actuator device in a liquid jet head. Ink jet recording heads are a typical type of liquid jet head. For example, an ink jet recording head includes a vibration plate defining a part of a pressure generating chamber communicating with nozzle apertures through which ink droplets are ejected. In the ink jet recording head, a piezoelectric element deforms the vibration plate to apply a pressure to the ink in the pressure generating chamber, thereby ejecting ink droplets through the nozzle apertures.
The piezoelectric material used for forming the piezoelectric layer of such a piezoelectric element is required to have high piezoelectric properties, and a typical example of the piezoelectric material is lead zirconate titanate (PZT) (see PTL 1). On the other hand, piezoelectric materials containing no lead or a reduced amount of lead are required from the viewpoint of environmental issues. For example, BiFeO3-based piezoelectric materials, which contain Bi and Fe, are lead-free piezoelectric materials (see, for example, PTL 2).